Added tests for changeset upload code. Refactored diff reading code and put it into...

diff --git a/app/controllers/changeset_controller.rb b/app/controllers/changeset_controller.rb
index 8151d3a677c3cadb85a7f796fd5460026cf8a8ea..a24f61e2838e9278e65f81184706d2e6ede11579 100644 (file)
--- a/app/controllers/changeset_controller.rb
+++ b/app/controllers/changeset_controller.rb
@@ -2,6 +2,7 @@
 
 class ChangesetController < ApplicationController
   require 'xml/libxml'
 
 class ChangesetController < ApplicationController
   require 'xml/libxml'

+  require 'diff_reader'

 
   before_filter :authorize, :only => [:create, :update, :delete, :upload]
   before_filter :check_write_availability, :only => [:create, :update, :delete, :upload]
 
   before_filter :authorize, :only => [:create, :update, :delete, :upload]
   before_filter :check_write_availability, :only => [:create, :update, :delete, :upload]


@@ -70,102 +71,37 @@ class ChangesetController < ApplicationController
     end
   end
 
     end
   end
 

+  ##
+  # Upload a diff in a single transaction.
+  #
+  # This means that each change within the diff must succeed, i.e: that
+  # each version number mentioned is still current. Otherwise the entire
+  # transaction *must* be rolled back.
+  #
+  # Furthermore, each element in the diff can only reference the current
+  # changeset.
+  #
+  # Returns: ??? the new document? updated diffs?

   def upload
   def upload

-    unless request.put?
+    # only allow POST requests, as the upload method is most definitely
+    # not idempotent, as several uploads with placeholder IDs will have
+    # different side-effects.
+    # see http://www.w3.org/Protocols/rfc2616/rfc2616-sec9.html#sec9.1.2
+    unless request.post?

       render :nothing => true, :status => :method_not_allowed
       return
     end
 
       render :nothing => true, :status => :method_not_allowed
       return
     end
 

-    p = XML::Reader.new request.raw_post
-
-    node_ids, way_ids, rel_ids = {}, {}, {}
-    ids = {"node"=>node_ids, "way"=>way_ids, "relation"=>rel_ids}
-
-    models = {"node"=>Node, "way"=>Way, "relation"=>Relation}
-
-    # FIXME shouldn't this be done through the 
-    # res = OSM::API.new.get_xml_doc
-    # as everything else is?
-    res = XML::Document.new
-    res.encoding = 'UTF-8'
-    root = XML::Node.new 'osm'
-    root['version'] = API_VERSION
-    root['creator'] = 'OpenStreetMap.org'
-    res.root = root
-
-    root << XML::Node.new_comment(" Warning: this is a 0.6 result document, " +
-      "not a normal OSM file. ")
-
+    changeset = Changeset.find(params[:id])
+    
+    diff_reader = DiffReader.new(request.raw_post, changeset)

     Changeset.transaction do
     Changeset.transaction do

-      while p.read == 1
-        break if p.node_type == 15 # end element
-        next unless p.node_type == 1 # element
-
-        case p.name
-        when 'create':
-            while p.read == 1
-            break if p.node_type == 15 # end element
-            next unless p.node_type == 1 # element
-
-            model = models[p.name]
-            next if model.nil?
-
-            elem = XML::Node.new p.name
-            nd = p.expand; p.next
-            osm = model.from_xml_node(nd, true)
-            elem['old_id'] = nd['id']
-
-            case nd.name
-            when 'way':
-                fix_way(osm, node_ids)
-              raise OSM::APIPreconditionFailedError.new if !osm.preconditions_ok?
-            when 'relation':
-                fix_rel(osm, ids)
-              raise OSM::APIPreconditionFailedError.new if !osm.preconditions_ok?
-            end
-
-            create_prim ids[nd.name], osm, nd
-            elem['new_id'] = osm.id.to_s
-            elem['new_version'] = osm.version.to_s
-            root << elem
-          end
-        when 'modify':
-            while p.read == 1
-            break if p.node_type == 15 # end element
-            next unless p.node_type == 1 # element
-
-            model = models[p.name]
-            next if model.nil?
-
-            elem = XML::Node.new p.name
-            new_osm = model.from_xml_node(p.expand); p.next
-            osm = model.find(new_osm.id)
-            osm.update_from new_osm, @user
-            elem['old_id'] = elem['new_id'] = osm.id.to_s
-            elem['new_version'] = osm.version.to_s
-            root << elem
-          end
-        when 'delete':
-            while p.read == 1
-            break if p.node_type == 15 # end element
-            next unless p.node_type == 1 # element
-
-            model = models[p.name]
-            next if model.nil?
-
-            elem = XML::Node.new p.name
-            osm = model.find(p.expand['id']); p.next
-            osm.delete_with_history(@user)
-            elem['old_id'] = elem['new_id'] = osm.id.to_s
-            elem['new_version'] = osm.version.to_s
-            root << elem
-          end
-        end
-      end
+      result = diff_reader.commit
+      render :text => result.to_s, :content_type => "text/xml"

     end
     end

-
-    render :text => res.to_s, :content_type => "text/xml"
-
+    
+  rescue ActiveRecord::RecordNotFound
+    render :nothing => true, :status => :not_found

   rescue OSM::APIError => ex
     render ex.render_opts
   end
   rescue OSM::APIError => ex
     render ex.render_opts
   end

diff --git a/app/models/node.rb b/app/models/node.rb
index c2a61906b1a1dc60d6e360d30d435d11ce3eebac..67efeca2c1a471f2e78d3bc9e6b1ef0d7b3244d5 100644 (file)
--- a/app/models/node.rb
+++ b/app/models/node.rb
@@ -75,20 +75,25 @@ class Node < ActiveRecord::Base
   def self.from_xml_node(pt, create=false)
     node = Node.new
     
   def self.from_xml_node(pt, create=false)
     node = Node.new
     

-    node.version = pt['version'].to_i

     node.lat = pt['lat'].to_f
     node.lon = pt['lon'].to_f
     node.changeset_id = pt['changeset'].to_i
 
     return nil unless node.in_world?
 
     node.lat = pt['lat'].to_f
     node.lon = pt['lon'].to_f
     node.changeset_id = pt['changeset'].to_i
 
     return nil unless node.in_world?
 

+    # version must be present unless creating
+    return nil unless create or not pt['version'].nil?
+    node.version = pt['version'].to_i
+

     unless create
       if pt['id'] != '0'
         node.id = pt['id'].to_i
       end
     end
 
     unless create
       if pt['id'] != '0'
         node.id = pt['id'].to_i
       end
     end
 

-    node.visible = pt['visible'] and pt['visible'] == 'true'
+    # visible if it says it is, or as the default if the attribute
+    # is missing.
+    node.visible = pt['visible'].nil? or pt['visible'] == 'true'

 
     if create
       node.timestamp = Time.now
 
     if create
       node.timestamp = Time.now


@@ -235,4 +240,11 @@ class Node < ActiveRecord::Base
     @tags[k] = v
   end
 
     @tags[k] = v
   end
 

+  ##
+  # dummy method to make the interfaces of node, way and relation
+  # more consistent.
+  def fix_placeholders!(id_map)
+    # nodes don't refer to anything, so there is nothing to do here
+  end
+

 end
 end

diff --git a/app/models/relation.rb b/app/models/relation.rb
index db4dd52a6799f68960b32a001bf1d0b7b50626c7..81f17899739ce336a6d6b1151befc9bbd4d44ca6 100644 (file)
--- a/app/models/relation.rb
+++ b/app/models/relation.rb
@@ -320,4 +320,22 @@ class Relation < ActiveRecord::Base
   def tags_as_hash
     return self.tags
   end
   def tags_as_hash
     return self.tags
   end

+
+  ##
+  # if any members are referenced by placeholder IDs (i.e: negative) then
+  # this calling this method will fix them using the map from placeholders 
+  # to IDs +id_map+. 
+  def fix_placeholders!(id_map)
+    self.members.map! do |type, id, role|
+      old_id = id.to_i
+      if old_id < 0
+        new_id = id_map[type.to_sym][old_id]
+        raise "invalid placeholder" if new_id.nil?
+        [type, new_id, role]
+      else
+        [type, id, role]
+      end
+    end
+  end
+

 end
 end

diff --git a/app/models/way.rb b/app/models/way.rb
index 1304d8a184da14254064c732ae252b4db6978756..b413ccb280d24c4e56fdb287b4b57a3029298ed0 100644 (file)
--- a/app/models/way.rb
+++ b/app/models/way.rb
@@ -299,4 +299,21 @@ class Way < ActiveRecord::Base
   def tags_as_hash
     return self.tags
   end
   def tags_as_hash
     return self.tags
   end

+
+  ##
+  # if any referenced nodes are placeholder IDs (i.e: are negative) then
+  # this calling this method will fix them using the map from placeholders 
+  # to IDs +id_map+. 
+  def fix_placeholders!(id_map)
+    self.nds.map! do |node_id|
+      if node_id < 0
+        new_id = id_map[:node][node_id]
+        raise "invalid placeholder for #{node_id.inspect}: #{new_id.inspect}" if new_id.nil?
+        new_id
+      else
+        node_id
+      end
+    end
+  end
+

 end
 end

diff --git a/config/routes.rb b/config/routes.rb
index e49cdf74e7d80acc64aa07a8b5d14d5bc29b1c28..39e2a1e749cd0cc95b223a91d689c7c70cd4a2ab 100644 (file)
--- a/config/routes.rb
+++ b/config/routes.rb
@@ -4,7 +4,7 @@ ActionController::Routing::Routes.draw do |map|
   map.connect "api/capabilities", :controller => 'api', :action => 'capabilities'
   
   map.connect "api/#{API_VERSION}/changeset/create", :controller => 'changeset', :action => 'create'
   map.connect "api/capabilities", :controller => 'api', :action => 'capabilities'
   
   map.connect "api/#{API_VERSION}/changeset/create", :controller => 'changeset', :action => 'create'

-  map.connect "api/#{API_VERSION}/changeset/upload", :controller => 'changeset', :action => 'upload'
+  map.connect "api/#{API_VERSION}/changeset/:id/upload", :controller => 'changeset', :action => 'upload', :id => /\d+/

   map.connect "api/#{API_VERSION}/changeset/:id", :controller => 'changeset', :action => 'read', :id => /\d+/
   map.connect "api/#{API_VERSION}/changeset/:id/close", :controller => 'changeset', :action => 'close', :id =>/\d+/
   
   map.connect "api/#{API_VERSION}/changeset/:id", :controller => 'changeset', :action => 'read', :id => /\d+/
   map.connect "api/#{API_VERSION}/changeset/:id/close", :controller => 'changeset', :action => 'close', :id =>/\d+/
   


@@ -22,6 +22,7 @@ ActionController::Routing::Routes.draw do |map|
   map.connect "api/#{API_VERSION}/way/:id/history", :controller => 'old_way', :action => 'history', :id => /\d+/
   map.connect "api/#{API_VERSION}/way/:id/full", :controller => 'way', :action => 'full', :id => /\d+/
   map.connect "api/#{API_VERSION}/way/:id/relations", :controller => 'relation', :action => 'relations_for_way', :id => /\d+/
   map.connect "api/#{API_VERSION}/way/:id/history", :controller => 'old_way', :action => 'history', :id => /\d+/
   map.connect "api/#{API_VERSION}/way/:id/full", :controller => 'way', :action => 'full', :id => /\d+/
   map.connect "api/#{API_VERSION}/way/:id/relations", :controller => 'relation', :action => 'relations_for_way', :id => /\d+/

+  map.connect "api/#{API_VERSION}/way/:id/:version", :controller => 'old_way', :action => 'version', :id => /\d+/, :version => /\d+/

   map.connect "api/#{API_VERSION}/way/:id", :controller => 'way', :action => 'read', :id => /\d+/, :conditions => { :method => :get }
   map.connect "api/#{API_VERSION}/way/:id", :controller => 'way', :action => 'update', :id => /\d+/, :conditions => { :method => :put }
   map.connect "api/#{API_VERSION}/way/:id", :controller => 'way', :action => 'delete', :id => /\d+/, :conditions => { :method => :delete }
   map.connect "api/#{API_VERSION}/way/:id", :controller => 'way', :action => 'read', :id => /\d+/, :conditions => { :method => :get }
   map.connect "api/#{API_VERSION}/way/:id", :controller => 'way', :action => 'update', :id => /\d+/, :conditions => { :method => :put }
   map.connect "api/#{API_VERSION}/way/:id", :controller => 'way', :action => 'delete', :id => /\d+/, :conditions => { :method => :delete }

diff --git a/lib/diff_reader.rb b/lib/diff_reader.rb
new file mode 100644 (file)
index 0000000..eca6d43
--- /dev/null
+++ b/lib/diff_reader.rb
@@ -0,0 +1,167 @@
+##
+# DiffReader reads OSM diffs and applies them to the database.
+#
+# Uses the streaming LibXML "Reader" interface to cut down on memory
+# usage, so hopefully we can process fairly large diffs.
+class DiffReader
+  include ConsistencyValidations
+
+  # maps each element type to the model class which handles it
+  MODELS = { 
+    "node"     => Node, 
+    "way"      => Way, 
+    "relation" => Relation
+  }
+
+  ##
+  # Construct a diff reader by giving it a bunch of XML +data+ to parse
+  # in OsmChange format. All diffs must be limited to a single changeset
+  # given in +changeset+.
+  def initialize(data, changeset)
+    @reader = XML::Reader.new data
+    @changeset = changeset
+  end
+
+  ##
+  # An element-block mapping for using the LibXML reader interface. 
+  #
+  # Since a lot of LibXML reader usage is boilerplate iteration through
+  # elements, it would be better to DRY and do this in a block. This
+  # could also help with error handling...?
+  def with_element
+    # skip the first element, which is our opening element of the block
+    @reader.read
+    # loop over all elements. 
+    # NOTE: XML::Reader#read returns 0 for EOF and -1 for error.
+    while @reader.read == 1
+      break if @reader.node_type == 15 # end element
+      next unless @reader.node_type == 1 # element
+      yield @reader.name
+    end
+  end
+
+  ##
+  # An element-block mapping for using the LibXML reader interface. 
+  #
+  # Since a lot of LibXML reader usage is boilerplate iteration through
+  # elements, it would be better to DRY and do this in a block. This
+  # could also help with error handling...?
+  def with_model
+    with_element do |model_name|
+      model = MODELS[model_name]
+      raise "Unexpected element type #{model_name}, " +
+        "expected node, way, relation." if model.nil?
+      yield model, @reader.expand
+      @reader.next
+    end
+  end
+
+  ##
+  # Checks a few invariants. Others are checked in the model methods
+  # such as save_ and delete_with_history.
+  def check(model, xml, new)
+    raise OSM::APIBadXMLError.new(model, xml) if new.nil?
+    unless new.changeset_id == @changeset.id 
+      raise OSM::APIChangesetMismatchError.new(new.changeset_id, @changeset.id)
+    end
+  end
+
+  ##
+  # Consume the XML diff and try to commit it to the database. This code
+  # is *not* transactional, so code which calls it should ensure that the
+  # appropriate transaction block is in place.
+  #
+  # On a failure to meet preconditions (e.g: optimistic locking fails) 
+  # an exception subclassing OSM::APIError will be thrown.
+  def commit
+
+    node_ids, way_ids, rel_ids = {}, {}, {}
+    ids = { :node => node_ids, :way => way_ids, :relation => rel_ids}
+
+    result = OSM::API.new.get_xml_doc
+
+    # loop at the top level, within the <osmChange> element (although we
+    # don't actually check this...)
+    with_element do |action_name|
+      if action_name == 'create'
+        # create a new element. this code is agnostic of the element type
+        # because all the elements support the methods that we're using.
+        with_model do |model, xml|
+          new = model.from_xml_node(xml, true)
+          check(model, xml, new)
+
+          # when this element is saved it will get a new ID, so we save it
+          # to produce the mapping which is sent to other elements.
+          placeholder_id = xml['id'].to_i
+          raise OSM::APIBadXMLError.new(model, xml) if placeholder_id.nil?
+
+          # some elements may have placeholders for other elements in the
+          # diff, so we must fix these before saving the element.
+          new.fix_placeholders!(ids)
+
+          # set the initial version to zero and save (which increments it)
+          new.version = 0
+          new.save_with_history!
+          
+          # save placeholder => allocated ID map
+          ids[model.to_s.downcase.to_sym][placeholder_id] = new.id
+
+          # add the result to the document we're building for return.
+          xml_result = XML::Node.new model.to_s.downcase
+          xml_result["old_id"] = placeholder_id.to_s
+          xml_result["new_id"] = new.id.to_s
+          xml_result["new_version"] = new.version.to_s
+          result.root << xml_result
+        end
+        
+      elsif action_name == 'modify'
+        # modify an existing element. again, this code doesn't directly deal
+        # with types, but uses duck typing to handle them transparently.
+        with_model do |model, xml|
+          # get the new element from the XML payload
+          new = model.from_xml_node(xml, false)
+          check(model, xml, new)
+
+          # and the old one from the database
+          old = model.find(new.id)
+
+          new.fix_placeholders!(ids)
+          old.update_from(new, @changeset.user)
+
+          xml_result = XML::Node.new model.to_s.downcase
+          xml_result["old_id"] = old.id.to_s
+          xml_result["new_id"] = new.id.to_s
+          xml_result["new_version"] = new.version.to_s
+          result.root << xml_result
+        end
+
+      elsif action_name == 'delete'
+        # delete action. this takes a payload in API 0.6, so we need to do
+        # most of the same checks that are done for the modify.
+        with_model do |model, xml|
+          new = model.from_xml_node(xml, false)
+          check(model, xml, new)
+
+          old = model.find(new.id)
+
+          # can a delete have placeholders under any circumstances?
+          # if a way is modified, then deleted is that a valid diff?
+          new.fix_placeholders!(ids)
+          old.delete_with_history!(new, @changeset.user)
+
+          xml_result = XML::Node.new model.to_s.downcase
+          xml_result["old_id"] = old.id.to_s
+          result.root << xml_result
+        end
+
+      else
+        # no other actions to choose from, so it must be the users fault!
+        raise "Unknown action #{action_name}, choices are create, modify, delete."
+      end
+    end
+
+    # return the XML document to be rendered back to the client
+    return result
+  end
+
+end

diff --git a/lib/osm.rb b/lib/osm.rb
index e9d3c946468723af7ce34ad96eada774b864838c..246fedf54b915dd066263e90afc2642689f5a6f3 100644 (file)
--- a/lib/osm.rb
+++ b/lib/osm.rb
@@ -54,6 +54,32 @@ module OSM
     end
   end
 
     end
   end
 

+  # Raised when a diff is uploaded containing many changeset IDs which don't match
+  # the changeset ID that the diff was uploaded to.
+  class APIChangesetMismatchError < APIError
+    def initialize(provided, allowed)
+      @provided, @allowed = provided, allowed
+    end
+    
+    def render_opts
+      { :text => "Changeset mismatch: Provided #{@provided} but only " +
+        "#{@allowed} is allowed.", :status => :conflict }
+    end
+  end
+
+  # Raised when bad XML is encountered which stops things parsing as
+  # they should.
+  class APIBadXMLError < APIError
+    def initialize(model, xml)
+      @model, @xml = model, xml
+    end
+
+    def render_opts
+      { :text => "Cannot parse valid #{@model} from xml string #{@xml}",
+        :status => :bad_request }
+    end
+  end
+

   # Raised when the provided version is not equal to the latest in the db.
   class APIVersionMismatchError < APIError
     def initialize(provided, latest)
   # Raised when the provided version is not equal to the latest in the db.
   class APIVersionMismatchError < APIError
     def initialize(provided, latest)

diff --git a/test/functional/changeset_controller_test.rb b/test/functional/changeset_controller_test.rb
index 1e050a71e0d722aabb3a20bdd6f6d53451cf9b3b..946d139d8714bdd90d8f622e06ca922a72c09171 100644 (file)
--- a/test/functional/changeset_controller_test.rb
+++ b/test/functional/changeset_controller_test.rb
@@ -44,6 +44,7 @@ class ChangesetController; def rescue_action(e) raise e end; end
     basic_authorization "test@openstreetmap.org", "test"
     content "<osm><changeset></osm>"
     put :create
     basic_authorization "test@openstreetmap.org", "test"
     content "<osm><changeset></osm>"
     put :create

+    assert_response :bad_request, "creating a invalid changeset should fail"

   end
 
   def test_read
   end
 
   def test_read


@@ -53,9 +54,331 @@ class ChangesetController; def rescue_action(e) raise e end; end
   def test_close
     
   end
   def test_close
     
   end

-  
-  def test_upload
+
+  ##
+  # upload something simple, but valid and check that it can 
+  # be read back ok.
+  def test_upload_simple_valid
+    basic_authorization "test@openstreetmap.org", "test"
+
+    # simple diff to change a node, way and relation by removing 
+    # their tags
+    diff = <<EOF
+<osmChange>
+ <modify>
+  <node id='1' lon='0' lat='0' changeset='1' version='1'/>
+  <way id='1' changeset='1' version='1'>
+   <nd ref='3'/>
+  </way>
+ </modify>
+ <modify>
+  <relation id='1' changeset='1' version='1'>
+   <member type='way' role='some' ref='3'/>
+   <member type='node' role='some' ref='5'/>
+   <member type='relation' role='some' ref='3'/>
+  </relation>
+ </modify>
+</osmChange>
+EOF
+
+    # upload it
+    content diff
+    post :upload, :id => 1
+    assert_response :success, 
+      "can't upload a simple valid diff to changeset: #{@response.body}"
+
+    # check that the changes made it into the database
+    assert_equal 0, Node.find(1).tags.size, "node 1 should now have no tags"
+    assert_equal 0, Way.find(1).tags.size, "way 1 should now have no tags"
+    assert_equal 0, Relation.find(1).tags.size, "relation 1 should now have no tags"
+  end

     
     

+  ##
+  # upload something which creates new objects using placeholders
+  def test_upload_create_valid
+    basic_authorization "test@openstreetmap.org", "test"
+
+    # simple diff to create a node way and relation using placeholders
+    diff = <<EOF
+<osmChange>
+ <create>
+  <node id='-1' lon='0' lat='0' changeset='1'>
+   <tag k='foo' v='bar'/>
+   <tag k='baz' v='bat'/>
+  </node>
+  <way id='-1' changeset='1'>
+   <nd ref='3'/>
+  </way>
+ </create>
+ <create>
+  <relation id='-1' changeset='1'>
+   <member type='way' role='some' ref='3'/>
+   <member type='node' role='some' ref='5'/>
+   <member type='relation' role='some' ref='3'/>
+  </relation>
+ </create>
+</osmChange>
+EOF
+
+    # upload it
+    content diff
+    post :upload, :id => 1
+    assert_response :success, 
+      "can't upload a simple valid creation to changeset: #{@response.body}"
+
+    # check the returned payload
+    assert_select "osm[version=#{API_VERSION}][generator=\"OpenStreetMap server\"]", 1
+    assert_select "osm>node", 1
+    assert_select "osm>way", 1
+    assert_select "osm>relation", 1
+
+    # inspect the response to find out what the new element IDs are
+    doc = XML::Parser.string(@response.body).parse
+    new_node_id = doc.find("//osm/node").first["new_id"].to_i
+    new_way_id = doc.find("//osm/way").first["new_id"].to_i
+    new_rel_id = doc.find("//osm/relation").first["new_id"].to_i
+
+    # check the old IDs are all present and negative one
+    assert_equal -1, doc.find("//osm/node").first["old_id"].to_i
+    assert_equal -1, doc.find("//osm/way").first["old_id"].to_i
+    assert_equal -1, doc.find("//osm/relation").first["old_id"].to_i
+
+    # check the versions are present and equal one
+    assert_equal 1, doc.find("//osm/node").first["new_version"].to_i
+    assert_equal 1, doc.find("//osm/way").first["new_version"].to_i
+    assert_equal 1, doc.find("//osm/relation").first["new_version"].to_i
+
+    # check that the changes made it into the database
+    assert_equal 2, Node.find(new_node_id).tags.size, "new node should have two tags"
+    assert_equal 0, Way.find(new_way_id).tags.size, "new way should have no tags"
+    assert_equal 0, Relation.find(new_rel_id).tags.size, "new relation should have no tags"

   end
   end

-  
+    
+  ##
+  # test a complex delete where we delete elements which rely on eachother
+  # in the same transaction.
+  def test_upload_delete
+    basic_authorization "test@openstreetmap.org", "test"
+
+    diff = XML::Document.new
+    diff.root = XML::Node.new "osmChange"
+    delete = XML::Node.new "delete"
+    diff.root << delete
+    delete << current_relations(:visible_relation).to_xml_node
+    delete << current_relations(:used_relation).to_xml_node
+    delete << current_ways(:used_way).to_xml_node
+    delete << current_nodes(:node_used_by_relationship).to_xml_node
+
+    # upload it
+    content diff
+    post :upload, :id => 1
+    assert_response :success, 
+      "can't upload a deletion diff to changeset: #{@response.body}"
+
+    # check that everything was deleted
+    assert_equal false, Node.find(current_nodes(:node_used_by_relationship).id).visible
+    assert_equal false, Way.find(current_ways(:used_way).id).visible
+    assert_equal false, Relation.find(current_relations(:visible_relation).id).visible
+    assert_equal false, Relation.find(current_relations(:used_relation).id).visible
+  end
+
+  ##
+  # test that deleting stuff in a transaction doesn't bypass the checks
+  # to ensure that used elements are not deleted.
+  def test_upload_delete_invalid
+    basic_authorization "test@openstreetmap.org", "test"
+
+    diff = XML::Document.new
+    diff.root = XML::Node.new "osmChange"
+    delete = XML::Node.new "delete"
+    diff.root << delete
+    delete << current_relations(:visible_relation).to_xml_node
+    delete << current_ways(:used_way).to_xml_node
+    delete << current_nodes(:node_used_by_relationship).to_xml_node
+
+    # upload it
+    content diff
+    post :upload, :id => 1
+    assert_response :precondition_failed, 
+      "shouldn't be able to upload a invalid deletion diff: #{@response.body}"
+
+    # check that nothing was, in fact, deleted
+    assert_equal true, Node.find(current_nodes(:node_used_by_relationship).id).visible
+    assert_equal true, Way.find(current_ways(:used_way).id).visible
+    assert_equal true, Relation.find(current_relations(:visible_relation).id).visible
+  end
+
+  ##
+  # upload something which creates new objects and inserts them into
+  # existing containers using placeholders.
+  def test_upload_complex
+    basic_authorization "test@openstreetmap.org", "test"
+
+    # simple diff to create a node way and relation using placeholders
+    diff = <<EOF
+<osmChange>
+ <create>
+  <node id='-1' lon='0' lat='0' changeset='1'>
+   <tag k='foo' v='bar'/>
+   <tag k='baz' v='bat'/>
+  </node>
+ </create>
+ <modify>
+  <way id='1' changeset='1' version='1'>
+   <nd ref='-1'/>
+   <nd ref='3'/>
+  </way>
+  <relation id='1' changeset='1' version='1'>
+   <member type='way' role='some' ref='3'/>
+   <member type='node' role='some' ref='-1'/>
+   <member type='relation' role='some' ref='3'/>
+  </relation>
+ </modify>
+</osmChange>
+EOF
+
+    # upload it
+    content diff
+    post :upload, :id => 1
+    assert_response :success, 
+      "can't upload a complex diff to changeset: #{@response.body}"
+
+    # check the returned payload
+    assert_select "osm[version=#{API_VERSION}][generator=\"OpenStreetMap server\"]", 1
+    assert_select "osm>node", 1
+    assert_select "osm>way", 1
+    assert_select "osm>relation", 1
+
+    # inspect the response to find out what the new element IDs are
+    doc = XML::Parser.string(@response.body).parse
+    new_node_id = doc.find("//osm/node").first["new_id"].to_i
+
+    # check that the changes made it into the database
+    assert_equal 2, Node.find(new_node_id).tags.size, "new node should have two tags"
+    assert_equal [new_node_id, 3], Way.find(1).nds, "way nodes should match"
+    Relation.find(1).members.each do |type,id,role|
+      if type == 'node'
+        assert_equal new_node_id, id, "relation should contain new node"
+      end
+    end
+  end
+    
+  ##
+  # create a diff which references several changesets, which should cause
+  # a rollback and none of the diff gets committed
+  def test_upload_invalid_changesets
+    basic_authorization "test@openstreetmap.org", "test"
+
+    # simple diff to create a node way and relation using placeholders
+    diff = <<EOF
+<osmChange>
+ <modify>
+  <node id='1' lon='0' lat='0' changeset='1' version='1'/>
+  <way id='1' changeset='1' version='1'>
+   <nd ref='3'/>
+  </way>
+ </modify>
+ <modify>
+  <relation id='1' changeset='1' version='1'>
+   <member type='way' role='some' ref='3'/>
+   <member type='node' role='some' ref='5'/>
+   <member type='relation' role='some' ref='3'/>
+  </relation>
+ </modify>
+ <create>
+  <node id='-1' changeset='4'>
+   <tag k='foo' v='bar'/>
+   <tag k='baz' v='bat'/>
+  </node>
+ </create>
+</osmChange>
+EOF
+    # cache the objects before uploading them
+    node = current_nodes(:visible_node)
+    way = current_ways(:visible_way)
+    rel = current_relations(:visible_relation)
+
+    # upload it
+    content diff
+    post :upload, :id => 1
+    assert_response :conflict, 
+      "uploading a diff with multiple changsets should have failed"
+
+    # check that objects are unmodified
+    assert_nodes_are_equal(node, Node.find(1))
+    assert_ways_are_equal(way, Way.find(1))
+  end
+    
+  ##
+  # upload multiple versions of the same element in the same diff.
+  def test_upload_multiple_valid
+    basic_authorization "test@openstreetmap.org", "test"
+
+    # change the location of a node multiple times, each time referencing
+    # the last version. doesn't this depend on version numbers being
+    # sequential?
+    diff = <<EOF
+<osmChange>
+ <modify>
+  <node id='1' lon='0' lat='0' changeset='1' version='1'/>
+  <node id='1' lon='1' lat='0' changeset='1' version='2'/>
+  <node id='1' lon='1' lat='1' changeset='1' version='3'/>
+  <node id='1' lon='1' lat='2' changeset='1' version='4'/>
+  <node id='1' lon='2' lat='2' changeset='1' version='5'/>
+  <node id='1' lon='3' lat='2' changeset='1' version='6'/>
+  <node id='1' lon='3' lat='3' changeset='1' version='7'/>
+  <node id='1' lon='9' lat='9' changeset='1' version='8'/>
+ </modify>
+</osmChange>
+EOF
+
+    # upload it
+    content diff
+    post :upload, :id => 1
+    assert_response :success, 
+      "can't upload multiple versions of an element in a diff: #{@response.body}"
+  end
+
+  ##
+  # upload multiple versions of the same element in the same diff, but
+  # keep the version numbers the same.
+  def test_upload_multiple_duplicate
+    basic_authorization "test@openstreetmap.org", "test"
+
+    diff = <<EOF
+<osmChange>
+ <modify>
+  <node id='1' lon='0' lat='0' changeset='1' version='1'/>
+  <node id='1' lon='1' lat='1' changeset='1' version='1'/>
+ </modify>
+</osmChange>
+EOF
+
+    # upload it
+    content diff
+    post :upload, :id => 1
+    assert_response :conflict, 
+      "shouldn't be able to upload the same element twice in a diff: #{@response.body}"
+  end
+
+  ##
+  # try to upload some elements without specifying the version
+  def test_upload_missing_version
+    basic_authorization "test@openstreetmap.org", "test"
+
+    diff = <<EOF
+<osmChange>
+ <modify>
+  <node id='1' lon='1' lat='1' changeset='1'/>
+ </modify>
+</osmChange>
+EOF
+
+    # upload it
+    content diff
+    post :upload, :id => 1
+    assert_response :bad_request, 
+      "shouldn't be able to upload an element without version: #{@response.body}"
+  end
+

 end
 end